org.taverna.server.master.rest.handler.InputStreamMessageHandler.java Source code

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Here is the source code for org.taverna.server.master.rest.handler.InputStreamMessageHandler.java

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/*
 * Copyright (C) 2010-2012 The University of Manchester
 * 
 * See the file "LICENSE.txt" for license terms.
 */
package org.taverna.server.master.rest.handler;

import static java.lang.Long.parseLong;
import static javax.ws.rs.core.MediaType.APPLICATION_OCTET_STREAM;
import static org.apache.commons.logging.LogFactory.getLog;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.List;

import javax.ws.rs.Consumes;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyReader;
import javax.ws.rs.ext.Provider;

import org.apache.commons.logging.Log;

/**
 * Maps a stream from a client into a bounded ordinary input stream that the
 * webapp can work with more easily.
 * 
 * @author Donal Fellows
 */
@Provider
@Consumes(APPLICATION_OCTET_STREAM)
public class InputStreamMessageHandler implements MessageBodyReader<InputStream> {
    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return InputStream.class.isAssignableFrom(type);
    }

    @Override
    public InputStream readFrom(Class<InputStream> type, Type genericType, Annotation[] annotations,
            MediaType mediaType, MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
            throws IOException, WebApplicationException {
        return new TransferStream(entityStream, httpHeaders.get("Content-Length"));
    }
}

/**
 * The actual transfer thunk.
 * 
 * @author Donal Fellows
 */
class TransferStream extends InputStream {
    private static final Log log = getLog("Taverna.Server.Handlers");

    public TransferStream(InputStream entityStream, List<String> contentLength) {
        this.entityStream = new BufferedInputStream(entityStream);
        if (contentLength != null && contentLength.size() > 0) {
            this.limit = parseLong(contentLength.get(0));
            log.debug("will attempt to transfer " + this.limit + " bytes");
        } else {
            this.limit = -1;
            log.debug("will attempt to transfer until EOF");
        }
    }

    InputStream entityStream;
    long limit;
    long doneBytes = 0;

    @Override
    public int read() throws IOException {
        if (limit >= 0 && doneBytes >= limit)
            return -1;
        int result = entityStream.read();
        if (result >= 0)
            doneBytes++;
        return result;
    }

    @Override
    public int read(byte[] ary, int off, int len) throws IOException {
        if (limit >= 0) {
            if (doneBytes >= limit)
                return -1;
            if (doneBytes + len > limit)
                len = (int) (limit - doneBytes);
        }
        int readBytes = entityStream.read(ary, off, len);
        if (readBytes >= 0)
            doneBytes += readBytes;
        return readBytes;
    }

    @Override
    public void close() throws IOException {
        entityStream.close();
    }
}